I dont use miner personally. Miner's income in empire will depend on mineral prices where you sell minerals, competitors in you systems etc. If you use courier bot you can get 3kkk doing 4 lvl missions in 30 days running 12h a day. By the time of testing I did not filter corporations with low LP/ISK rate, so final result might be even better. Also courier is much safer as nobody will petition you. You can use it 15h/day without getting caught (*). Should I increase courier bot price so people finally realize that courier is the best bot here?
(*)I am testing now 6h online with 3h offline intervals (timer 4 settings) and no problems for 2 months with 5 couriers.